In the past, pouches have been formed, filled and sealed in a variety of ways. Some prior devices operated on an intermittent basis, which is not generally conducive to efficiency where pouches must be formed, filled and sealed at higher rates than intermittent motion machines can effectively produce.
In one prior continuous operation, such as illustrated in U.S. Pat. No. 3,821,873, expressly incorporated herein by reference as if fully set out herein, pouches are formed by folding a pouch web lengthwise, creating transverse seals across the folded web to form a series of pouches in a pouch train by running the folded web around a horizontally disposed wheel where spaced heated sealing lands seal the web together, transporting the web train around a filler wheel, filling pouches as the train is moved around the filler, sealing the open pouch tops, then cutting pouches from the train at pouch edges defined by the cut lines along the transverse seal areas. Such pouch forming, filling and sealing equipment is very efficient and operates at relatively high speeds compared to an intermittent pouch operation.
While such equipment works well for pouches of a given pitch or width, use of the same equipment to form, fill and seal pouches of significantly different widths requires a significant number of major change parts. For example, the entire web sealer wheel and entire filler wheel structure must typically be changed out.
See, for example, the pouch machine disclosed in U.S. Pat. No. 5,502,951, which is expressly incorporated herein by reference. That machine handles a degree of pouch width variations by use of coordinated sealer wheel and filler wheel change parts, whose drives are mechanically linked in cooperation. The number of pouch stations on the sealer must be associated in whole number relation to those on the filler wheel about which the pouch train is engaged on vacuum lands.
In this application, the phrase “pouch width” is used to refer to that distance from one vertical pouch edge to the opposite vertical edge of the same pouch when the pouches are oriented with their mouths above their folded bottom and the edges extend between the mouths and the bottom on both sides of the pouch. The “width” is typically extended in the same direction the pouches move through the pouch forming sealers and pouch fillers.
The term “pitch” generally refers to the distance from one point of a pouch to the identical point on an immediately preceding or succeeding pouch. Thus, pouch “pitch” might be, for example, that distance from a leading edge of one pouch to the same leading edge of an immediately following pouch, however it is transported.
The phrase “pitch line” is used to identify the line or path that pouches follow through the process.
As used herein, the terms “wheel” and “filler wheel” refer to any wheel-like or annular structure operable as described herein and including but not limited to a solid, circular disk, or annulus or ring, or other shaped configuration or structure capable of carrying the gripper units or pouch supporting lands as described herein about or through a curved or circular pouch pitch line or path for filling, and through a variety of stages or sectors as described herein.
In other prior U.S. Pat. Nos. 6,657,165 and 6,917,014, a horizontally oriented sealer wheel is provided with heated sealing lands which have slight radial adjustments to permit some adjustment between the parallel transverse seals, but the adjustment provided is insufficient to provide the extent of pouch width size adjustment now desired in the industry, such as for pouches ranging from about 2.5 inches to about 5.5 inches in major width. Major change parts are required and the changeover procedures are time consuming, but necessary for a pouch operation with the capacity to handle a wide range of pouch widths.
It is now desired in the industry to have equipment capable of continuously forming, filling and sealing pouches having widths varying in different pouch runs from about 2.5 inches width (seal-to-seal) to about 5.5 inches width, and at high speeds up to about 500 pouches per minute on the sealer wheel. And at the filler wheel, depending on the pitch or number of stations around the circumference of a given filler wheel, throughput speeds of up to 3750 inches per minute (at the pouch path) are desired. While prior apparatus has provided some degree of adjustability, for slighter pouch width variations than noted above, there is no known equipment capable of handling pouches at high speed and in the now desired width range without significant changeover parts, time and cost.
In another aspect of such pouch operations, consideration must be given to the handling of the pouch web on the sealer wheel.
In the typical prior operation, the folded web is disposed horizontally around a horizontally disposed sealer wheel on a vertical axis and having a plurality of spaced heated sealing lands against which the web is tensioned. Such wheels and lands are constructed so that traverse seals are created across the web plies from the bottom web fold line to the open top edges of the plies. Such sealer wheels work well in continuous operation but accommodation must be made for operational or “cycle stops” where the process and the web must be stopped momentarily, or for an extensive time. Heat from the lands transfers into the stopped web at the seals and the seal propagation in the web at the seals can unduly widen the seals or the excessive heat transfer due to extended dwell time can even burn through the web, breaking the web on the wheel or otherwise rendering pouches on the wheel unusable on system start. In the past, such sealers have sometimes been referred to as “vertical sealers”, but this refers to the orientation of the seal in the pouch web sides when the folded web is vertically oriented, and not to the orientation of the sealer wheel itself, which is typically horizontal, rotating about a vertical axis.
It is thus desirable to provide a continuous web sealer where, nevertheless, undue heat transfer and seal propagation on cycle stops is eliminated.
In another typical system for forming, filling and sealing pouches, the pouches are cut apart from the pouch train before filling. Such apparatus is clearly described and shown in U.S. Pat. No. 4,956,964 which is expressly incorporated herein by reference as if fully expressly set forth herein. These pouches are delivered to a pair of pouch gripping jaws carried on a carrier chain. The leading edge or seal of the pouch is gripped by a leading gripper jaw of the jaw pair, while the trailing pouch edge or seal is gripped by a trailing gripper jaw, generally at a distance below the open pouch mouth which is directed upwardly. These jaws are relatively movable with respect to each other to allow the pouch to be opened and filled. The individual pouches are then sealed and discharged.
In this system, the gripper jaws are carried by chains drawn around respective sprockets. These require maintenance and are somewhat noisy compared to systems where the uncut pouch train engages with filler wheel lands and is filled about a filler wheel which had no chains, sprockets or grippers.
It will thus be appreciated that systems for handling a wide range of pouch widths or pitch in the now desired range of about 2.5 to 5.5 inches and at effective pouch machine speeds up to about 3750 inches per minute must take into account numerous pouch handling functions of filling, sealing and cutting. Sealing apparatus must be capable of producing final pouch seals in the pouch web for the extremes of pouch sizes and provision must be made to eliminate seal propagation, burn through or heat caused pouch destruction during cycle stops, similar to those issues in the pouch forming process. Moreover, provisions must be made to accommodate the varied pouch width extremes on the filler wheel, and provisions must be made for accurately cutting pouch after pouch from either the formed or filled web within the seal areas. All this must be accomplished on a continuous basis with as little pouch rejection as possible, for the noted wide range of possible pouch widths. The cost of obtaining a plurality of machines, each to handle a single pouch size, even if slightly variable by adjustment within a very narrow range, is prohibitively expensive, and at the least takes up too much production floor space.
In another consideration of pouching operations, there is a concern of cleanliness resulting from stray product. Frequently, the product loaded into the pouches is a powder, fine particles or a frangible product. Stray product contaminates pouching apparatus and requires frequent wash down or cleaning. Where the pouch apparatus is fully integrated, cleaning of the filling area where pouches are filled and most likely to have stray product involves or intrudes into other components of the equipment, whether cleaning is needed there or not.
It has been one objective of the invention to provide an improved pouch forming, filling and sealing apparatus and methods capable of handling a wide range of pouch widths at high speed.
A further objective of one embodiment of the invention has been to provide apparatus and methods for forming, filling and sealing pouches in a wide range of pouch widths while requiring only minimal, if any, change parts.
A further objective of the invention has been to provide apparatus and methods for producing transverse seals in a folded pouch web and which does not conduct destructive or excessive heat into the web on cycle stops, such that undue heat or seal propagation into the web is eliminated.
A further objective of the invention in an alternate embodiment is to provide apparatus and methods for forming, filling and sealing pouches in a wide range of pouch widths wherein change parts are used in sub assemblies smaller, lighter, easier to handle and more repeatable than prior devices requiring more major and potentially more expensive change parts.
A further objective of one embodiment of the invention has been to provide a rotary knife apparatus wherein the hubs can be changed to accommodate pouch width changes in a wide range, but without excessive drive lash in the hub drives.
A further objective of one embodiment of the invention has been to provide an improved pouch forming, filling and sealing apparatus in combination with a rotary knife for accommodating a wide range of pouch widths but without mechanical adjustment or replacement of major and minor knife hubs.